1. Field of the Invention
This invention relates to a lead acid battery and, in particular, to structures of its grids and elements.
2. Description of Prior Art
In conventional lead acid batteries, positive and negative plates used comprise grids composed of lead alloy and filled with active material, and lead alloy is also used as connectors for the connection of cells. However, such lead alloy has relatively high specific resistance, as for a metal, of about 2.5 .times. 10.sup..sup.-5 .omega..cm at 25.degree.C and, hence, batteries of conventional structure can not supply high electric power because of their high internal resistance.
The object of this invention is to provide a lead acid battery having reduced internal resistance and, particularly, of higher power per unit volume (W/L). This invention relates to a lead acid battery having elements comprising a plurality of positive and negative plates which are composed of grids formed with band-shaped portions at one end facing to the side wall of a container, and layered one upon another with separators put therebetween in such a way that the respective band-shaped portions for the positive plates and negative plates respectively face to the opposing side walls of the container, the positive plates and the negative plates being respectively connected at least at a part of the length of said band-shaped portions to thereby form straps.